Correlating cancer induction with specific mutations is critically dependent on the availability of technologies that can effectively screen for unknown mutations in several genes simultaneously. This proposal will optimize and streamline a newly developed technology (ALBUMS) for the sensitive and large scale screening of base substitutions, which are the mutations predominantly generated by a wide range of mutagens and are found in several human cancers. DNA from cancerous and normal cells are annealed and hybridized to generate mismatches at the positions of base substitutions. ALBUMS utilizes the covalent and specific binding of novel molecules at unique chemical groups (aldehydes) generated at the position of mismatches by highly specific mismatch - recognition enzymes, in order to isolate mutation - containing DNA. The microplate-based design of the assay allows to screen hundreds or thousands of diverse genes simultaneously, isolate those with mutations and apply them on existing large - scale hybridization DNA arrays for a single - step identification of the mutated genes. The R21 phase (feasibility) will (a) define the optimal operating conditions for detecting and isolating mutation-containing genes (genotypic selection). ALBUMS will be used to isolate cDNA from a single mutated gene (p53) in the presence of increasing amounts of normal alleles, and also to detect p53 mutants in cell lines known to contain p53 mutations. And (b) will establish feasibility for the single-step screening of several hundred or thousands of human genes by combining ALBUMS and commercial DNA hybridization arrays (chips). The second phase (R33) will develop technology to screen in a single step hundreds or thousands of genes in human tumor samples for mutations, on DNA chips. Sets of mutations will be mapped and verified by conventional sequencing in order to establish the utility of the new technology to define the molecular profile of cancer. In the last step, this high throughput technology will be streamlined to provide a procedure with easy access to researchers and clinicians for cost - effective, large - scale mutation screening of cancer samples. Further envisioned ALBUMS applications include genotyping and polymorphism studies and role of mutations in diseases other than cancer.